This invention relates to ostomy pouches having vent openings and, in particular, to pouches having both vent openings and deodorizing filters with means for sealing the vent openings until such time as it is desired to vent gases from the pouch.
It is known in the art to provide ostomy appliances having vents that are normally closed but may be opened when users wish to allow flatus to escape from and thereby deflate such pouches. For example, U.S. Pat. No. 3,759,260 discloses an ostomy pouch having a vent opening that is normally sealed by a panel, flap or tab adhesively secured to the outer surface of the pouch over the opening. When deflation of the pouch is desired, the adhesive seal is broken and, after such venting has occurred, the vent is resealed. The effectiveness of the resealing depends on the security of adhesive reattachment; if adhesion is lacking because of moisture or other causes, subsequent leakage of gases and liquids may result.
It is also known to provide pouches with continuously-open vents equipped with porous filters having absorbent materials, such as finely-divided activated carbon, capable of deodorizing gases. The aforemention U.S. Pat. No. 3,759,260 also discloses such a filter in the form of a fibrous disc located within a pouch over a vent opening, the surface of the disc facing into the pouch being covered by an impervious panel so that gases escaping from the pouch must travel along a labyrinthine path in generally radial directions between the periphery of the filter and the vent opening. If such a filter were instead located on the outside of the pouch, then the operation would be essentially the same but the direction of radial flow through the filter would be reversed. In either case, such a filter is accessible to fluids and solids collected by the pouch, especially when the wearer is reclining or has assumed a position other than standing. Contact between the pouch's liquid/solid contents and the filter may clog such a filter and reduce or destroy its gas-filtering capability.
U.S. Pat. No. 4,203,445 discloses an ostomy appliance in which a deodorizing filter unit is mounted within a pouch adjacent the vent opening of that pouch. The filter unit is multi-layered, being composed of a fibrous core layer containing activated carbon and protective covering layers 19 and 20. Both of the covering layers are gas-transmissible but liquid impervious. While the cover layers may prevent direct contact between the fibrous filter and liquid, such cover layers (especially the inner layer 19) may themselves become obstructed in use and therefore interfere with the gas filtering/deodorizing/ venting action that the unit is designed to provide.
Other patents representative of the state of the art are U.S. Pat. Nos. 5,250,042 and 4,449,970.
An important aspect of this invention lies in providing an ostomy pouch having a vent opening, preferably one associated with a deodorizing filter element, which is inaccessible to the contents of the pouch and which is inoperative in venting gases from the pouch until such time as the wearer squeezes the pouch in the vicinity of the vent to open a normally-closed protective valve located within the pouch.
The valve takes the form of a flexible plastic dome secured to the interior surface of a pouch wall over the vent opening in that wall. A linear slit is provided in the dome with the edges of the slit normally sealing against each other to prevent the passage of gases, liquids and solids. In a preferred embodiment of the invention, an odor-absorbing filter extends across the vent opening, either along the inner surface of the pouch wall within the dome or along the outer surface of the pouch wall over and about the vent opening. Because the dome functions as a normally-closed valve, venting of the pouch does not occur until such time as such valve is opened. Opening is achieved simply by squeezing the dome between the fingers in directions extending inwardly from generally opposite ends of the slit, causing the edges of the slit to buckle and allowing gases to exit through the valve opening. The squeezing force is applied externally of the pouch--that is, the thin, flexible wall of the pouch in the vicinity of the dome is squeezed in a manner that deforms the dome and spreads the edges of the slit. Because of shape-recovering elastic memory of the polymeric material from which the dome is formed, the opening closes as soon as the squeezing force is discontinued and the protective function of the dome is restored.
The dome may be generally circular or rectangular in outline. Its linear slit preferably extends in either a generally vertical or generally horizontal direction when the pouch is worn. Since ostomy pouches are customarily elongate in a vertical direction, the slit is therefore preferably oriented either longitudinally or transversely to the direction of pouch elongation. To open the protective valve and vent a pouch, a user need only squeeze the dome between the thumb and index finger with the thumb exerting force from one end of the slit and the index finger exerting force from the opposite end.
Other features, objects, and advantages of the invention will become apparent from the specification and drawings.